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(11) | EP 0 009 160 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | High efficiency catalyst for polymerizing olefins, and the use thereof |
| (57) Catalyst compositions exhibiting high activity for the polymerization of a-olefins
are prepared by reacting (A) tetravalent or trivalent titanium compounds such as a
titanium tetraalkoxide, (B) an anhydrous nickel compound such as nickel chloride,
(C) an organomagnesium component such as a hydrocarbon soluble complex of dialkyl
magnesium and an alkyl aluminum, (D) a halide source such as a hydrogen halide or
an alkyl aluminum halide, and (E) an alkyl aluminum halide if not otherwise provided.
Polymerization processes employing this catalyst composition do not require subsequent
catalyst removal steps and the resulting polymers have broader molecular weight distributions
than do corresponding polymers prepared without the added anhydrous nickel compound. |
[0001] This invention relates to a new catalyst composition suitable for the polymerization of a-olefins and to a polymerization process employing such a catalyst composition.
[0002] It is well known that olefins such as ethylene, propylene and 1-butene can be polymerized in the presence ot metallic catalysts, particularly the reaction products of organometallic compounds and transition metal compounds, to form substantially unbranced polymers of relatively high molecular weight. Typically such polymerizations are carried out at relatively low temperatures and pressures in an inert organic liquid diluent or carrier. Following polymerization, it is common to remove catalyst residues from the polymer by repeatedly treating the polymer with alcohol or other deactivating agent such as aqueous base. Such catalyst deactivation and/or removal procedures are expensive both in time and material consumed as well as the equipment required to carry out such treatment.
[0003] Furthermore, most of the known catalyst systems are more efficient in preparing polyolefins in slurry (i.e., wherein the polymer is not dissolved in the carrier) than in solution (i.e., wherein the temperature is high enough to solubilize the polymer in the carrier). The lower efficiencies of such catalysts in solution polymerization are generally believed to be caused by the general tendency of the catalysts to become rapidly depleted or deactivated by the higher temperatures normally employed in solution processes. Also, processes involving the copolymerization of ethylene with higher a-olefins exhibit catalyst efficiencies significantly lower than ethylene homopolymerization processes.
[0004] Recently, catalysts having'higher efficiencies have been disclosed as illustrated by Scata U.S. Patent 4,115,319. While the increased efficiencies achieved by using these recent catalysts are significant, even higher efficiencies are desirable particularly in production of copolymers such as ethylene/hexene-1 or ethylene/octene-1 having a low melt index at densities below 0.920 g/cc.
[0005] Also, these high efficiency catalyst generally produce polymers of relatively narrow molecular weight distribution. It is therefore desirable to have, for some applications such as injection molding, high efficiency catalysts which produce polymers and copolymers having a broader molecular weight distribution.
[0006] The present invention, in one aspect, is a catalyst composition suitable for the polymerization of a-olefins and prepared by reaction of: (A) a tetravalent titanium compound or a complex of a trivalent titanium compound with an electron donor, (B) an anhydrous divalent nickel compound, (C) an organomagnesium component, (D) a halide source and (E) an alkylaluminum halide. The magnesium component is (1) an organomagnesium compound or (2) a complex of an organomagnesium compound and an organometallic compound in an amount sufficient to solubilize the organomagnesium compound in a hydrocarbon solvent. The halide source is a non-metallic halide corresponding to the formula R'X wherein R' is hydrogen or an active monovalent organic radical and X is halogen. Alternatively, the halide source is a metallic halide correspond-. ing to the formula MRy-aXa wherein Group 2B, 3A or 4A of Mendeleev's Periodic Table of the Elements, R is a monovalent organic radical usually hydrocarbyl or hydrocarbyloxy, X is halogen, y is a number corresponding to valence of M and a is a number from 1 to y. The alkylaluminum halide has the formula AlRy'Xy" wherein R is a monovalent organic radical and y' and y" each have a value of from zero to three with the sum of y' and y" being three.
[0007] The proportions of the components of the catalyst reactants are such that the atomic ratios of the elements are:
Mg:Ti is from 1:1 to 2000:1, preferably from 5:1 to 200:1; most preferably from 5:1 to 75:1;
Al:Ti is from 0.1:1 to 2000:1, preferably from 0.5:1 to 200:1; most preferably from 1:1 to 75:1;
Ni:Ti is from 0.01:1 to 500:1; preferably from 0.01:1 to 100:1; most preferably from 1:1 to 40:1;
excess X:A1 is from 0.002:1 to 10:1, preferably from 0.002:1 to 2:1, most preferably from 0.01:1 to 1.4:1.
[0008] The "excess X" is excess halide above that which would be theoretically required to convert the magnesium and nickel compounds to the dihalide if they were not added in dihalide form.
[0009] In a second aspect, the invention is a process for polymerizing a-olefins under conditions characteristic of Ziegler polymerization wherein the above catalyst is employed as the sole catalyst. These catalysts are capable of producing more than a million pounds of olefin polymer or copolymer per pound of transition metal. The resulting polymers generally contain lower amounts of catalyst residues than polymers produced with conventional catalyst even after treating to remove the catalyst. Further, these polymers have a relatively broad molecular weight distribution.
[0010] The present invention is most advantageously practiced in a polymerization process wherein an a-olefin is polymerized, generally in the presence of hydrogen as a molecular weight control agent, in a polymerization zone containing an inert diluent and the catalyst. The polymerization is most beneficially carried out under inert atmosphere and relatively low temperature and pressure, although very high pressures are optionally employed.
[0011] Olefins which are suitably homopolymerized or copolymerized in the practice of this invention are aliphatic a-monoolefins or a-diolefins having from 2 to 18 carbon atoms. Illustrative of such a-olefins are ethylene, propylene, butene-I, pen- tene-1, 3-methylbutene-1, 4-methylpentene-l, hexene-1, octene-1, dodecene-1, octadecene-1, 1,7-octadiene and the like. It is understood that a-olefins may be copolymerized with other a-olefins and/or with small amounts i.e., up to about 25 weignt percent based on the polymer of other ethylenically unsalurated monomers such as styrene, a-methylstyrene and similar ethylenically unsaturated monomers which do not destroy conventional Ziegler catalysts. Most benefits are realized in the polymerization of aliphatic a-monoolefins, particularly ethylene and mixtures of ethylene and up to 50, especially from 0.1 to 40 weight percent of propylene, butene-1, hexene-1, octene-1, 4-methylpentene-l, 1,7-octadiene or similar higher a-olefin or diolefin based on total monomer.
[0012] The anhydrous nickel compound (B) is required to obtain the broader molecular weight distribution. Suitable nickel compounds include those nickel compounds represented by the formula Ni(Q)n wherein Q is an anion such as halide, particularly chloride or bromide, hydroxide, carboxylate, carbonate, nitrate, sulfate or mixtures thereof and n is two (2) divided by the valence of Q. Paticularly suitable nickel compounds are C1-C12 carboxylates, and preferably C6-C10 carboxylates. Hydrocarbon soluble nickel carboxylates such as, for example, nickel 2-ethylhexanoate or naphthenate are particularly preferred since they form a smaller particle size nickel chloride when prereacted with a suitable halogen source. However, it is not necessary to prereact the nickel carboxylate with a halide source.
[0013] Advantageously, the tetravalent titanium compound has the empirical formula: TiXn(OR)4-n wherein X is a halogen, particularly chlorine or bromine, R is an alkyl or an aryl group having from 1 to 12 carbon atoms and n has a value of 0 to 4. Such titanium compounds are preferably derived from the titanium halides wherein one or more of the halogen atoms are replaced by an alkoxy or aryloxy group. Exemplary of such compounds include tetrabutoxy titanium, tetra(isopropoxy) titanium, dibutoxy titanium dichloride, monoethoxy titanium trichloride, tetraphenoxy titanium and the like.
[0014] Advantageously, the trivalent titanium complex has the empirical formula: TiX3(L)x wherein X is halide, and L is an electron donating compound such as water or an organic electron donor, e.g., alcohol, ether, ketone, amine or olefin, and x is a number from 1 to 6. Usually, the organic electron donor has from 1 to 12 carbon atoms and donates an unshared pair of electrons to the complex. In preferred complexes, X is chloride or bromide, most preferably chloride and L is alcohol, especially an aliphatic alcohol having 2 to 8 carbon atoms and most preferably 3 to 6 carbon atoms such as isopropyl alcohol, n-propyl alcohol, n-butyl alcohol and isobutyl alcohol. While the exact structure of the complex is not known, it is believed to contain 3 valence bonds to the halide ions and 1 to 6, preferably 2 to 4 coordination bonds to the electron donating compound.
[0015] The titanium halide complex is most advantageously prepared by heating the trivalent titanium halide dispersed in the electron donating compound under nitrogen or similar inert atmosphere. Usually the formation of the complex is visually indicated by a definite change in color. For example, when the dark purple α-TiCl3 is heated in anhydrous iso- dark purple α-TiCl3 is heated anhydrous propyl alcohol under nitrogen, complex formation is indicated by the formation of a brilliant blue solution. The complex is normally solid, but liquid complexes can be used.
[0016] In addition to a α-TiCl3, the Δ, y and crystalline forms of titanium trichloride are advantageously employed in the preparation of the complex. Also suitable are titanium tribromide, titanium trifluoride and the like. Of the foregoing, the Δ- and a- forms of titanium trichloride are preferred. Exemplary electron donating compounds include C1-C10 aliphatic alcohols, e.g., isopropyl alcohol, ethanol, n-propyl alcohol, butanol and others; C1-C12 ethers, ketones, aldehydes, amines and olefins; and water.
[0017] The preferred organomagnesium component is a hydrocarbon soluble complex of the formula MgR"2·xMR"y wherein R" is a hydrocarbyl or hydrocarbyloxy, M is aluminum, zinc or mixtures thereof and x is about 0.001 to 10, especially from about 0.15 to about 2.5, and y denotes the number of hydrocarbyl groups which corresponds to the valence of M. As used herein, hydrocarbyl and hydrocarbyloxy are monovalent hydrocarbon radicals. Preferably, hydrocarbyl is alkyl, cycloalkyl, aryl, aralkyl, alkenyl and similar hydrocarbon radicals having 1 to 20 carbon atoms, with alkyl having 1 to 10 carbon atoms being especially preferred. Likewise, preferably, hydrocarbyloxy is alkoxy, cycloalkyloxy, aryloxy, aralkyloxy, alkenyloxy and similar oxyhydrocarbon radicals having 1 to 20 carbon atoms, with alkyloxy having 1 to 10 car-. bon atoms preferred. Hydrocarbyl is preferred over hydrocarbyloxy.
[0018] This complex is prepared by reacting particulate magnesium such as magnesium turnings, or magnesium particles with about a stoichiometric amount of hydrocarbyl or hydrocarbyloxy halide, illustrated as R'X. The resulting hydrocarbon insoluble MgR"2 is solubilized by adding the organometallic compound such as AlR"3 or mixtures thereof with ZnR"2. The amount of organometallic compounds which is added to the MgR"2 to form the organomagnesium complex should be enough to solubilize a significant amount of MgR"2, e.g., at least 5 weight percent, preferably at least 50 weight percent, and especially preferred all the MgR"2' When employing a mixture of AlR"3 and ZnR"2 to solubilize MgR"2, the atomic ratio of Zn to Al is from about 3000:1 to about 0.1:1, preferably from about 350:1 to about 1:1.
[0019] In order to obtain maximum catalyst efficiency at polymerization temperatures above 180°F, it is desirable to minimize the amount of aluminum in the complex and the total catalyst. Accordingly, for catalysts having Al:Ti atomic ratios less than 120:1, it is desirable to have a Mg:Al atomic ratio more than 0.3:1, preferably from about 0.5:1 to 10:1.
[0020] Other organometallic compounds than AlR"3' ZnR" or mixtures thereof can be used to solubilize the organomagnesium compound in hydrocarbon, usually in an amount sufficient to produce an atomic ratio of 0.01:1 to 10:1 of metal nf The organometallic compounds to magnesium. Examples of other organometallic compounds include boron trialkyls such as boron triethyl, alkyl silanes such as dimethyl silane and tetraethyl silane, alkyl-tin and alkyl phosphorous compounds.
[0021] Alternatively, organomagnesium compounds can be used without an aluminum or zinc complex particularly if rendered soluble in hydrocarbon by addition of ether, amine, etc. More recently, hydrocarbon soluble organomagnesium compounds have been prepared as taught in Kamienski et al. U.S. 3,646,231. These organomagnesium compounds are particularly desirable.
[0022] Preferably the organomagnesium compound is a hydrocarbon soluble dihydrocarbylmagnesium such as the magnesium dialkyls and the magnesium diaryls. Exemplary magnesium dialkyls include n-butyl-sec-butyl magnesium, diisopropyl magnesium, di-n-hexyl magnesium, isopropyl-n-butyl magensium, ethyl-n-hexyl magnesium, ethyl-n-butyl magnesium, di-n-octyl magnesium and others wherein alkyl has from 1 to 20 carbon atoms. Exemplary magnesium diaryls include diphenylmagnesium, dibenzylmag- nesium, and especially preferred ditolylmagnesium. Also suitable are alkyl and aryl magnesium alkoxides and aryloxides and aryl and alkyl magnesium halides with the halogen-free organomagnesium compounds being more desirable.
[0023] The preferred halide sources are the active non-metallic halides of the formula R'X including hydrogen halides and active organic halides such as t-alkyl halides, allyl halides, benzyl halides and other active hydrocarbyl halides. By an active organic halide is meant a hydrocarbyl halide that contains a labile halogen at least as active, i.e., as easily lost to another compound, as the halogen of sec-butyl chloride and preferably as active as t-butyl chloride. Active organic dihalides, trihalides and poly- halides are also suitably employed. Examples of preferred active non-metallic halides are hydrogen chloride, hydrogen bromide, t-butyl chloride, t-amyl bromide, allyl chloride, benzyl chloride, crotyl chloride, methylvinyl carbinyl chloride, a-phenylethyl bromide and diphenyl methyl chloride.
[0025] Suitable metallic halides as set forth by formula hereinbefore are organometallic halides and metal halides wherein the metal is in Group 2B, 3A or 4A, of Mendeleev's Periodic Table of Elements. Preferred metallic halides are aluminum halides of the formula AlR3-aXa wherein each R is independently hydrocarbyl such as alkyl, X is a halogen, and a is a number from 1 to 3. Most preferred are alkylaluminum halides such as ethylaluminum sesquichloride, diethyl-aluminum chloride, ethylaluminum dichloride, and diethyl-aluminum bromide, with ethylaluminum dichloride being especially preferred. Alternatively, a metal halide such as aluminum trichloride or a combination of aluminum trichloride with an alkyl aluminum halide or trialkyl aluminum compound may be employed.
[0026] The organic moieties of the aforementioned organomagnesium, e.g., R", and the organic moieties of the halide source, e.g., R and R', are suitably any other organic radical provided that they do not contain functional groups that poison conventional Ziegler catalysts. Preferably such organic moieties do not contain active hydrogen, i.e., those sufficiently active to react with the Zere- witinoff reagent.
[0027] In cases wherein neither the organomagnesium component nor the halide source contains aluminum, it is desirable to include in the total catalyst an aluminum compound such as an alkyl aluminum compound, e.g., a trialkyl aluminum, an alkyl aluminum halide or an aluminum halide.
[0028] In order to maximize catalyst efficiency, the catalyst is prepared by mixing the components of the catalyst in an inert liquid diluent in the following especially preferred order: nickel compound, organomagnesium compound, halide source and titanium compound or complex. Somewhat less preferred is the order of addition wherein the organomagnesium component is first added to an inert liquid diluent followed by the addition of the halide source, the nickel compound and then the titanium compound or complex. The foregoing catalyst components are combined in proportions sufficient to provide atomic ratios as previously mentioned.
[0029] In the most preferred manner, the nickel halide is preformed from the reaction of a hydrocarbon soluble nickel carboxylate such as nickel di-2-ethylhexanoate or nickel dinaphthenate with the halogen source in a hydrocarbon diluent which precipitates anhydrous nickel halide in a very fine particulate form.
[0030] If polymerization temperatures below 180°C are employed, the atomic ratios of Al:Ti may be from 0.1:1 to 2000:1, preferably from 1:1 to 200:1. However, when polymerization temperatures above 180°C are employed, the aluminum compound is used in proportions such that the Mg:Al ratio is more than 0.3:1, preferably from 0.5:1 to 10:1, and Al:Ti ratio is less than 120:1, preferably less than 75:1. The use of very low amounts of aluminum necessitates the use of high purity solvents or diluents in the polymerization zone and other components should be essentially free of impurities which react with aluminum alkyls. Otherwise additional quantities of an organomet- tallic compound must be used to react with such impurities. Moreover, in the catalyst the aluminum compound should be in the form of trialkyl aluminum or alkyl aluminum halide substantially free of alkyl aluminum dihalide.
[0031] The catalytic components are preferably combined in the presence of an inert liquid diluent such that the resultant catalyst slurry is from 0.005 to 1.0 molar (moles/liter) with respect to magnesium. Suitable inert organic diluents include liquefied ethane propane, isobutane, u-butane , n-hexane, the various isomeric hexanes, isooctane, paraffinic mixtures of alkanes having from 8 to 12 carbon atoms, cyclohexane, methylcyclopentane, dimethylcyclohexane, dodecane and industrial solvents composed of saturated or aromatic hydrocarbons such as kerosene, naphthas, etc., especially when freed of any olefin compounds and other impurities, and having boiling points in the range from -50° to 200°C. Also included as suitable inert diluents are benzene, toluene, ethylbenzene, cumene and decaline.
[0032] Mixing of the components to provide the desired catalyst is advantageously carried out under an inert atmosphere such as nitrgoen or argon at temperatures in the range from -100 to 200°C, preferably from 0° to 100°C. The mixing time is not critical as an active catalyst most often is formed in 1 minute or less. In the preparation of the catalyst, it in not necessary to separate hydrocarbon soluble and insoluble components.
[0033] Polymerization of a-olefins is effected by contacting a catalytic amount of the catalyst composition and the a-olefin monomer at temperatures in the range from 0 to 300°C, and preferably at solution polymerization temperatures, e.g., from 130° to 250°C, for a residence time of a few seconds to 48 hours or more, preferably 15 seconds to 2 hours. Also it is generally desirable to carry out the polymerization in the absence of moisture and oxygen using an inert liquid carrier which may be an organic diluent, solvnet, or excess monomer. Diluents employed in the catalyst preparation are particularly suitable.
[0034] To obtain maximum catalyst yields in terms of polymer weight per weight of titanium, sufficient catalyst should be used to provide from 0.0001 to 0.1 millimoles titanium per liter of diluent in the polymerization zone. However, the optimum catalyst concentration will depend upon polymerization conditions such as temperature, pressure, solvent and presence of catalyst poisons.
[0035] To realize the full benefit of the high efficiency catalyst, care must be taken to avoid oversaturation of the solvent with polymer.
[0036] To optimize catalyst yields in the polymerization of ethylene, it is preferable to maintain an ethylene concentration in the solvent in the range from 1 to 10 weight percent and most advantageously 1.2 to 2 weight percent. Also care must be taken to avoid oversaturation of the solvent with the resulting polymer. For best results, the amount of polymer in the carrier should not exceed about 50 weight percent based on the total weight of the reaction mixture.
[0037] Hydrogen can be employed in concentrations ranging from 0.001 to 1 mole per mole of monomer to reduce the molecular weight of the resultant polymer by addition with the monomer stream or other conventional means.
[0038] The preferred polymerization pressures are relatively low, e.g., from 50 to 1000 psig (3.5--70 kg/cm2 gauge) especially from 100 to 600 psig (7.0-42 kg/cm2 gauge). However, polymerization can occur at pressures from atmospheric to the pressure limit of the reactor. Stirring during polymerization is desirable to maintain better temperature control and more uniform concentrations throughout the polymerization zone.
[0039] The a-olefin monomer or mixture of monomers is contacted with the catalyst in the usual manner, preferably by bringing the catalyst and monomer together with intimate agitation provided by stirring or other means. Agitation can be continued during polymerization, but in some instances polymerization in an unstirred zone is desirable. Adequate means should be provided for dissipating the exothermic heat of polymerization. With more active catalyst, means for refluxing monomer and solvent is often advantageous.
[0040] The polymerization can be effected in batch or continuous manner, such as, for example, by passing the reaction mixture through an elongated reaction tube which is contacted externally with suitable cooling medium to maintain the desired reaction temperature, or by passing the reaction mixture through an equilibrium overflow reactor or a series of the same.
[0041] The polymer is recovered from the polymerization mixture by removing any unreacted monomer and solvent. No further purification is required. In some instances, however, it may be desirable to add a small amount of a conventional catalyst deactivating reagent. The resultant polymer contains insignificant amounts of catalyst residue and possesses a relatively broad molecular weight distribution.
[0042] The following examples are given to further illustrate the invention. All parts and percentages are by weight unless otherwise indicated. The melt index values 12 and I10 were determined by the method of ASTM D 1238-70 and the density values were determined by ASTM D 1248-74.
[0043] In Examples 1-7, the catalysts were prepared in n-heptane, 2,2,4-trimethylpentane or Isopar® E (a mixture of saturated isoparaffins having 8 to 9 carbon atoms) under nitrogen atmosphere containing less than 5 ppm oxygen and 5 ppm water. Polymerizations were carried out in five liter stainless steel stirred batch reactor using two liters of dry, oxygen-free Isopar® E as carrier diluents. After polymerization, the reactor contents were dumped into a beaker, cooled, and the polymer recovered, dried in a vacuum oven and analyzed. The melt index values I2 and I10 were determined by the method of ASTM D-1238-70 and the density values by the method of ASTM D-1248. Catalyst efficiencies are reported as grams of polyethylene per gram of titanium, gPE/gTi.
EXAMPLE 1 Polyethylene
A. Preparation of Anhydrous NiCl2
[0044] An anhydrous nickel chloride (NiCl2) slurry in isopar® E was prepared as follows. NiCl2·6H2O was heated in a vacuum oven at about 100°C for 8-10 hours. The resultant partially dried product was then extracted with n-propyl alcohol into Isopar® E to produce a fine slurry of anhydrous NiCl2 in Isopar® E. The n-propyl alcohol was then removed by distillation.
B. Preparation of the Catalyst Composition
[0045] The catalyst composition was prepared by adding with stirring to a 4-ounce (118 cc) serum bottle under a nitrogen atmosphere the following components in the indicated order:
[0046] 48.45 ml of Isopar® E 0.18 ml of 0.084 M anhydrous NiCl2 in Isopar® E 0.74 ml of 0.385 M Mg(n-Bu, sec-Bu) in Isopar® E 0.44 ml of 0.85 M EtAlCl2 in Isopar® E 0.19 ml of 0.04 M Ti(OiPr)4 in Isopar® E
[0048] The atomic ratios of the catalyst components were as follows:
Mg/Ti = 38:1 Al/Ti = 50:1 Ni/Ti = 2:1 excess Cl/Al = 24:50 = 0.48:1
C. Polymerization
[0049] Into the stirred 5-liter stainless steel reactor was added two liters of Isopar® E, 19 psig (1.3 kg/cm2 gauge) of hydrogen, 120 psig (8.4 kg/cm2 gauge) of ethylene. The reactor was heated to 150°C and then 10 ml (0.0015 millimoles Ti) of the above catalyst composition was added. The temperature was controlled at 150°C and the total pressure was maintained constant at 160 psiq (11.2 kg/cm2 gauge) for 20 minutes yielding 100 grams of polyethylene, a catalyst efficiency of 1.14 x 106 grams of polymer per gram of Ti. The polymer had a melt index (I2) of 4.35, a melt index (I10) of 38.72, an I10/I2 of 8.9 and a density of 0.9647 g/cc.
EXAMPLE 2 Ethylene/1-Hexene Copolymer
[0050] A. Employing the procedures of Example 1, a catalyst was prepared using the following components listed in order of addition:
42.12 ml of Isopar® E .45 ml of 0.084 M anhydrous NiCl2 5.8 ml of 0.045 M MgCl2 (prepared from HC1 and n-Bu-s-Bu-Mg) .09 ml of 0.85 M ethylaluminum dichloride .33 ml of 0.9 M aluminumtriethyl 1.21 ml of 0.0062 M TiCl3(iPrCH)x
[0051] The atomic ratios of this catalyst were as follows:
Mg/Ti = 35:1
Al/Ti = 50:1
Ni/Ti = 5:1 excess C1/A1 = 0.4:1
[0052] B. Polymerization was conducted as described in Example 1 at 150°C using twenty (20) milliliters of hexene-1, 20 psig (1.4 kg/cm2 gauge) H2 and 120 psig (8.4 kg/cm2 gauge) ethylene. The final reactor pressure was 165 psig (11.6 kg/cm2 gauge). Twenty milliliters (0.003 millimoles of Ti) of the catalyst yielded 156 grams of polymer for an effeciency of 1.1 x 106 g polymer/g Ti. The polymer had a broad molecular weight distribution with a high molecular weight tail as indicated by gel permeation chromatography and the following properties:
0.69 melt index (12) 8.14 (I10) 11.8 I10/ I2 0.9427 g/cc density
EXAMPLE 3
[0053] Following the general operating procedure of Example 1, several other catalysts prepared from anhydrous nickel chloride were evaluated with a total catalyst concentration of 0.001 millimolar based on Ti, 120 psig (8.4 kg/cm2 gauge) of ethylene and a polymerization temperature of 150°C. The catalysts are given in Table I and polymerization results in Table II.
EXAMPLE 4
A. Preparation of Anhydrous NiCl2
[0054] To a mixture of .60 gram (0.5 millimoles) of a nickel di-2-ethylhexanoate solution in mineral spirits containing 6% Ni by weight (commercially available from the Ventron Corp., Danvers, Mass.) and 97.8 ml of 2,2,4-trimethyl pentane (TMP) was added 1.65 ml of 0.94 M (1.5 moles) ethyl aluminum dichloride (EADC). Immediately upon addition of the EADC, a fine particle size, gold colored slurry of NiCl2 was formed.
B. Preparation of the Catalyst Composition
[0055] The catalyst was prepared by reacting at ambient temperature under a nitrogen atmosphere the following components in the indicated order:
94.47 ml TMP 3.0 ml of the 0.005 M Nicl2 in TMP 0.97 ml of 0.62 M butyl ethyl magensium (BEM) 0.64 ml of 0.94 M EADC 0.32 ml of 0.91 M triethylaluminum (ATB) in TMP 0.60 ml of 0.025 M tetra-isopropyl titanate (Ti(OiPr)4) in TMP.
[0057] The atomic ratios of the catalyst components were as follows:
Mg/Ti = 40:1 Al/Ti = 60:1 Ni/Ti = 1:1 excess Cl:Al = 0.1:1
C. Polymerization
[0058] As described in Example 1C, the 5-liter reactor charged with 2 liters of Isopar® E was heated to 150°C and then was added 19 psig (1.3 kg/cm2 gauge) of hydrogen and 160 psig (11.2 kg/cm2 gauge) of ethylene added for a total reactor pressure of 200 psig (14.0 kg/cm2 gauge). Twenty ml (0.003 moles of Ti) of the catalyst (4B) was injected into the reactor, and the pressure maintained at 200 psig (14.0 kg/cm2 gauge) with ethylene for 30 minutes. A yield of 177 gm of polyethylene (1.23 x 106 gm PE/gm Ti) was obtained with a melt index of 0.78, an I10 of 8.70, I10/I2 of 11.15, and a density of 0.9610.
EXAMPLE 5
[0059] Following the general procedure of Example 4, several other catalyst were prepared using NiCl2 formed in situ and evaluated using a total catalyst concentration of 0.001 millimolar based on Ti and a polymerization temperature of 150°C. Unless otherwise indicated the ethylene pressure was 120 psig (8.4 kg/cm2 gauge) and the total pressure was 160 psig (11.2 kg/cm2 gauge). Typical data are given in Tables III and IV.
EXAMPLE 6
[0060] Data from another series of catalysts prepared and evaluated as described in Example 4 are given in Tables V and VI. Unless otherwise indicated, the total catalyst concentration was 0.001 millimolar based on Ti, the polymerization temperature was 150°C, and the ethylene pressure was 160 psig (11.2 kg/cm2 gauge) and the total pressure 200 psig (14.0 kg/cm2 gauge).
EXAMPLE 7 Ethylene/1-Octene Copolymers
[0061] Data from another series of catalysts prepared as described in Example 4 and evaluated for the polymerization of ethylene/1-octene are given in Tables VII and VIII. Unless otherwise indicated, the total catalyst concentration was 0.001 millimolar based on Ti and the polymerization temperature was 150°C. The reactor was charged with 150 psig (10.5 kg/cm2 gauge) of ethylene, and 200 ml of 1-octene as comonomers. No hydrogen was added. The total reactor pressure was 200 psig (14.0 kg/cm2 gauge).
1. A catalyst composition suitable for the polymerization of a-olefins and prepared
by reaction of:
(A) a tetravalent titanium compound or a complex of a trivalent titanium compound with an electron donor,
(B) an anhydrous divalent nickel compound,
(C) an organomagnesium component selected from (1) an organomagnesium compound or (2) a complex of an organomagensium compound and an organometallic compound in an amount safficient to solubilize the organomagnesium compound in a hydrocarbon solvent,
(D) a halide source selected from (1) an active non-metallic halide, said non-metallic halide corresponding to the formula R'X wherein R' is hydrogen or an organic group at least as active as sec-butyl and X is halogen or (2) a metallic halide corresponding to the formula MRy-aXa wherein M is a metal of Group 2B, 3A or 4A of Mendeleev's Periodic Table of Elements, R is a monovalent organic radical, X is halogen, y is a number corresponding to the valence of M and a is a number of 1 to y, and
(E) an aluminum compound represented by the formula AlRy'Xy" wherein R and X are as defined above and y' and y" each have a value of from zero to three with the sum of y' and y" being three if the organomagnesium component (B) and/or the halide source (D) provides sufficient quantities of aluminum; provided that the proportions of components (A)-(E) are such that the atomic ratio of Mg:Ti is from 1:1 to 2000:1, the atomic ratio of Al:Ti is from 0.01:1 to 2000:1, the atomic ratio of Ni:Ti is from 0.01 to 500:1, the atomic ratio of excess halide:Al X is from 0.0005:1 to 10:1.
2. The catalyst composition of Claim 1 where the nickel compound (B) is nickel halide
and the atomic ratios of Mg:Ti, Al:Ti, Ni:Ti, and excess halide:Al are respectively
from 5:1 to 200:1, from 0.5:1 to 200:1, from 0.1:1 to 100:1, and from 0.002:1 to 2:1.
3. The catalyst composition of Claim 1 where the nickel compound (B) is nickel chloride,
the halide source (D) is an alkyl aluminum chloride, and the atomic ratios of Mg:Ti,
Al:Ti, Ni:Ti, and excess chloride:Al are respectively from 5:1 to 75:1, from 1:1 to
75:1, from 1:1 to 40:1, and from 0.01 to 1:4.
4. The catalyst composition of Claim 3 where the nickel compound (B) is a hydrocarbon
soluble nickel C1-C12 carboxylate.
5. The catalyst composition of Claim 3 where the nickel compound (B) is 2-ethylhexanoate
or nickel naphthenate and the halide source (D) is ethyl aluminum dichloride.
6. The catalyst composition of Claim 1 where the nickel chloride is formed in situ
by reaction of a hydrocarbon soluble nickel C6-C10 carboxylate with an active halide source (D).
7. The catalyst composition of Claim 1 where (a) is tetra(isopropoxy)titanium, (B)
is anhydrous nickel chloride, (C) is a dialkyl magnesium complex with ethyl aluminum
dichloride with an atomic ratio of Mg:Al of from 0.3:1 to 1000:1, (D) is hydrogen
chloride, diethyl aluminum chloride or ethyl aluminum dichloride; and the atomic ratios
of Mg:Ti, Al:Ti, Ni:Ti, and excess Cl:Al are respectively from 5:1 to 75:1, from 1:1
to 75:1, from 1:1 to 40:1, and from 0.01 to 1.4.
8. A process for the polymerization of an α-olefin under conditions characteristic
of Zeigler polymerization which comprises employing as the polymerization catalyst
the composition of any one of Claims 1 to 7.
9. The process of Claim 8 where the nickel compound is anhydrous nickel chloride.
10. The process of Claims 8 or 9 where the a-olefin is ethylene or a mixture of ethylene
and at least one other copolymerizable, ethylenically unsaturated monomer.